Answers

If you have a recent backup then restore that and use it. You might need to do a Load Whole Station which will reboot the controller and create a bump on the output signals.

If no backup is available or if it is from too far back, you can try to export the project to CSV, assuming you can do that without the error popping up.After successfully exporting the project, import it and create a new project that should be without damage. Go through the new project and check it for missing configuration parts. Those most probably caused the damage.

It is always a good idea to switch on the automatic backup in Freelance Engineering. Then you have a recent backup available all the time.